Browse
Submit Data
Databases
API
Help

Dataset Information

8 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

CeCl₃ /n-BuLi: Unraveling Imamoto's Organocerium Reagent.

ABSTRACT: CeCl₃ (thf) reacts at low temperatures with MeLi, t-BuLi, and n-BuLi to isolable organocerium complexes. Solvent-dependent extensive n-BuLi dissociation is revealed by ⁷ Li NMR spectroscopy, suggesting "Ce(n-Bu)₃ (thf)_x " or solvent-separated ion pairs like "[Li(thf)₄ ][Ce(n-Bu)₄ (thf)_y ]" as the dominant species of the Imamoto reagent. The stability of complexes Li₃ Ln(n-Bu)₆ (thf)₄ increases markedly with decreasing Ln^III size. Closer inspection of the solution behavior of crystalline Li₃ Lu(n-Bu)₆ (thf)₄ and mixtures of LuCl₃ (thf)₂ /n-BuLi in THF indicates occurring n-BuLi dissociation only at molar ratios of <1:3. n-BuLi-depleted complex LiLu(n-Bu)₃ Cl(tmeda)₂ was obtained by treatment of Li₂ Lu(n-Bu)₅ (tmeda)₂ with ClSiMe₃ , at the expense of LiCl incorporation. Imamoto's ketone/tertiary alcohol transformation was examined with 1,3-diphenylpropan-2-one, affording 99 % of alcohol.

SUBMITTER: Berger T

PROVIDER: S-EPMC8362106 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Direct electrophilic and radical isoperfluoropropylation with i-C3F7-Iodine(III) reagent (PFPI reagent).

Project description:The isoperfluoropropyl group (i-C3F7) is an emerging motif in pharmaceuticals, agrichemicals and functional materials. However, isoperfluoropropylated compounds remain largely underexplored, presumably due to the lack of efficient access to these compounds. Herein, we disclose the practical and efficient isoperfluoropropylation of aromatic C-H bonds through the invention of a hypervalent-iodine-based reagent-PFPI reagent, that proceeds via a Ag-X coupling process. The activation of the PFPI reagent without any catalysts or additives was demonstrated in the synthesis of isoperfluoropropylated electron-rich heterocycles, while its activity under photoredox catalysis was shown in the synthesis of isoperfluoropropylated non-activated arenes. Detailed mechanistic experiments and DFT calculations revealed a SET-induced concerted mechanistic pathway in the photoredox reactions. In addition, the unique conformation of i-C3F7 in products, that involved intramolecular hydrogen bond was investigated by X-ray single-crystal diffraction and variable-temperature NMR experiments.

| S-EPMC10449889 | biostudies-literature

A Versatile Silver(I) Pentafluorooxosulfate Reagent for the Synthesis of OSF5 Compounds.

Project description:Herein, we report the preparation of silver(I) pentafluorooxosulfate from commercially available AgF and OSF4 . The compound is surprisingly stable in a MeCN solution. Apart from that, AgOSF5 has been stabilised by the addition of 2,2'-bipyridine ligands. Starting from solutions of the unstabilised silver(I) salt, OSF5 complexes with NiII , CuI , and CuII -centres have been obtained. In addition, AgOSF5 has proven to be generally capable of mediating the transfer of OSF5 groups to aryne moieties, thus furnishing a new and safe method for the preparation of OSF5 -substituted arenes. X-ray crystal structure analysis of selected transition-metal OSF5 compounds have revealed distorted octahedral [OSF5 ]- anions which are extensively stabilised by hydrogen bonding.

| S-EPMC8456853 | biostudies-literature

A practical fluorosulfonylating platform via photocatalytic imidazolium-based SO2F radical reagent.

Project description:Sulfonyl fluorides are key components in the fields of chemical biology, materials science and drug discovery. In this line, the highly active SO2F radical has been employed for the construction of sulfonyl fluorides, but the utilization of gaseous ClSO2F as radical precursor is limited due to the tedious and hazardous preparation. Meanwhile, the synthesis of sulfonyl fluorides from inert SO2F2 gas through a fluorosulfonyl radical (·SO2F) process has met with inevitable difficulties due to the high homolytic bond dissociation energy of the S(VI)-F bond. Here we report a radical fluorosulfonylation strategy for the stereoselective synthesis of alkenyl sulfonyl fluorides and functional alkyl sulfonyl fluorides with an air-stable crystalline benzimidazolium fluorosulfonate cationic salt reagent. This bench-stable redox-active reagent offers a useful and operational protocol for the radical fluorosulfonylation of unsaturated hydrocarbons with good yield and high stereoselectivity, which can be further transformed into valuable functional SO2F moieties.

| S-EPMC9206656 | biostudies-literature

Synthesis and shift-reagent-assisted full NMR assignment of bacterial (Z8,E2,ω)-undecaprenol.

Project description:The repeating isoprene unit is a fundamental biosynthetic motif. The repetitive structure presents challenges both for synthesis and for structural characterization. In this synthesis of the (Z8,E2,ω)-undecaprenol of prokaryotic glycobiology, we exemplify solutions to these challenges. Allylation of sulfone-derived carbanions controlled the stereochemistry, and its proof-of-structure was secured by Eu(hfc)3 complexation to disperse the overlaid resonances of its 1H NMR spectrum.

| S-EPMC5749266 | biostudies-literature

Catalytic asymmetric nucleophilic fluorination using BF3·Et2O as fluorine source and activating reagent.

Project description:Fluorination using chiral catalytic methods could result in a direct access to asymmetric fluorine chemistry. However, challenges in catalytic asymmetric fluorinations, especially the longstanding stereochemical challenges existed in BF3·Et2O-based fluorinations, have not yet been addressed. Here we report the catalytic asymmetric nucleophilic fluorination using BF3·Et2O as the fluorine reagent in the presence of chiral iodine catalyst. Various chiral fluorinated oxazine products were obtained with good to excellent enantioselectivities (up to >99% ee) and diastereoselectivities (up to >20:1 dr). Control experiments (the desired fluoro-oxazines could not be obtained when Py·HF or Et3N·3HF were employed as the fluorine source) indicated that BF3·Et2O acted not only as a fluorine reagent but also as the activating reagent for activation of iodosylbenzene.

| S-EPMC8233348 | biostudies-literature

Unraveling the O2 Reduction Reaction on 2D Monolayer LaNiO3 Perovskite.

Project description:The O2 reduction reaction (ORR) occurring at cathodes is a critical reaction in many electrochemical energy-converting devices such as fuel cells. The reaction kinematics of the ORR is generally very slow with high overpotentials and needs to be enhanced by using an efficient electrocatalyst. The highly recognized Pt-based electrocatalyst needs to be replaced with a low-cost non-noble metal-based electrocatalyst for catalyzing the ORR. We theoretically studied the structural and electronic properties of 3D bulk LaNiO3 perovskite. We have cleaved the (0 0 1) surface from 3D LaNiO3, which has a zero band gap (E g), to create 2D monolayer LaNiO3 computationally and studied its electronic properties. Our study demonstrates that the 2D monolayer LaNiO3 is a suitable candidate for catalyzing the ORR because of its high catalytic activity with a tiny electronic band gap of 0.25 eV. We explored the ORR mechanism on the 2D monolayer LaNiO3 perovskite by inspecting each intermediate. Our present findings show that the 2D monolayer LaNiO3 can efficiently catalyze the ORR through a four-electron (4e-) reduction reaction due to the excellent catalytic activity of its basal plane, which accords with the experimental findings. The change in Gibbs free energy (ΔG) calculations of various intermediate steps of the ORR demonstrates that all reaction steps are spontaneous and thermodynamically favorable. The 2D monolayer LaNiO3 perovskite can be a potential candidate for catalyzing the ORR efficiently. This study helps to enable the development of high-activity, stable 2D perovskites for use in future solid oxide fuel cells and related applications in green energy technologies.

| S-EPMC11339991 | biostudies-literature

CS2/CO2 Utilization Using Mukaiyama Reagent as a (Thio)carbonylating Promoter: A Proof-of-Concept Study.

Project description:We report on the reaction of ethylene-terminated heteroatoms (C2X; X = N, O, and S) with CS2/CO2 using Mukaiyama reagent (2-chloro-1-methylpyridinium iodide, CMPI) as a promoter for the preparation of imidazolidin-2-one, oxazolidin-2-one, 1,3-dioxolan-2-one, 1,3-dithiolan-2-one, and their thione counterparts at ambient temperature and pressure. Spectroscopic measurements, viz., 1H/13C nuclear magnetic resonance (NMR) and ex situ attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy methods verified the reaction of CS2/CO2 with the ethylene-based substrates and subsequently the formation of cyclic products. The experimental data indicated the formation of the enol-form of imidazolidin-2-one and oxazolidin-2-one, while the keto-form was obtained for their thione correspondents. Furthermore, density functional theory calculations revealed the stability of the keto- over the enol-form for all reactions and pointed out the solvent effect in stabilizing the latter.

| S-EPMC9260919 | biostudies-literature

1,1-Difluoroethyl chloride (CH3CF2Cl), a novel difluoroalkylating reagent for 1,1-difluoroethylation of arylboronic acids.

Project description:1,1-Difluoroethylated aromatics are of great importance in medicinal chemistry and related fields. 1,1-Difluoroethyl chloride (CH3CF2Cl), a cheap and abundant industrial raw material, is viewed as an ideal 1,1-difluoroethylating reagent, but the direct introduction of the difluoroethyl (CF2CH3) group onto aromatic rings using CH3CF2Cl has not been successfully accomplished. Herein, we disclose a nickel-catalyzed 1,1-difluoroethylation of arylboronic acids with CH3CF2Cl for the synthesis of (1,1-difluoroethyl)arenes.

| S-EPMC9071211 | biostudies-literature

Unraveling the long-pursued Au144 structure by x-ray crystallography.

Project description:The transition from nanocluster to nanocrystal is a central issue in nanoscience. The atomic structure determination of metal nanoparticles in the transition size range is challenging and particularly important in understanding the quantum size effect at the atomic level. On the basis of the rationale that the intra- and interparticle weak interactions play critical roles in growing high-quality single crystals of metal nanoparticles, we have reproducibly obtained ideal crystals of Au144(SR)60 and successfully solved its structure by x-ray crystallography (XRC); this structure was theoretically predicted a decade ago and has long been pursued experimentally but without success until now. Here, XRC reveals an interesting Au12 hollow icosahedron in thiolated gold nanoclusters for the first time. The Au-Au bond length, close to that of bulk gold, shows better thermal extensibility than the other Au-Au bond lengths in Au144(SR)60, providing an atomic-level perspective because metal generally shows better thermal extensibility than nonmetal materials. Thus, our work not only reveals the mysterious, long experimentally pursued structure of a transition-sized nanoparticle but also has important implications for the growth of high-quality, single-crystal nanoparticles, as well as for the understanding of the thermal extensibility of metals from the perspective of chemical bonding.

| S-EPMC6184749 | biostudies-literature

Beyond Takai's Olefination Reagent: Persistent Dehalogenation Emerges in a Chromium(III)-μ3 -Methylidyne Complex.

Project description:Reaction of CHI3 with six equivalents of CrCl2 in THF at low temperatures affords [Cr3 Cl3 (μ2 -Cl)3 (μ3 -CH)(thf)6 ] as the first isolable high-yield CrIII μ3 -methylidyne complex. Substitution of the terminal chlorido ligands via salt metathesis with alkali-metal cyclopentadienides generates isostructural half-sandwich chromium(III)-μ3 -methylidynes [CpR 3 Cr3 (μ2 -Cl)3 (μ3 -CH)] (CpR =C5 H5 , C5 Me5 , C5 H4 SiMe3 ). Side and decomposition products of the Cl/CpR exchange reactions were identified and structurally characterized for [Cr4 (μ2 -Cl)4 (μ2 -I)2 (μ4 -O)(thf)4 ] and [(η5 -C5 H4 SiMe3 )CrCl(μ2 -Cl)2 Li(thf)2 ]. The Cl/CpR exchange drastically changed the ambient-temperature effective magnetic moment μeff from 9.30/9.11 μB (solution/solid) to 3.63/4.32 μB (CpR =C5 Me5 ). Reactions of [Cr3 Cl3 (μ2 -Cl)3 (μ3 -CH)(thf)6 ] with aldehydes and ketones produce intricate mixtures of species through oxy/methylidyne exchange, which were partially identified as radical recombination products through GC/MS analysis and 1 H NMR spectroscopy.

| S-EPMC8456800 | biostudies-literature